Data from: Niche specialization influences adaptive phenotypic plasticity in threespine stickleback

Phenotypic plasticity may be favored in generalist populations if it increases niche width, even in temporally constant environments. Phenotypic plasticity can increase the frequency of extreme phenotypes in a population and thus allow it to make use of a wide resource spectrum. Here we test the prediction that generalist populations should be more plastic than specialists. In a common-garden experiment, we show that solitary, generalist populations of threespine sticklebacks inhabiting small coastal lakes of British Columbia have a higher degree of morphological plasticity than the more specialized sympatric limnetic and benthic species. The ancestral marine stickleback showed low levels of plasticity similar to those of sympatric sticklebacks, implying that the greater plasticity of the generalist population has evolved recently. Measurements of wild populations show that those with mean trait values intermediate between the benthic and limnetic values indeed have higher morphological variation. Our data indicate that plasticity can evolve rapidly after colonization of a new environment in response to changing niche use.若表型可塑性（phenotypic plasticity）能够扩大生态位宽度，即便在时间恒定的环境中，该性状也可能在泛化种群中受到选择青睐。表型可塑性可提升种群中极端表型的出现频率，从而使种群能够利用更广泛的资源谱。本研究对“泛化种群的表型可塑性应高于特化种群”这一预测进行了验证。通过同质园实验（common-garden experiment），我们发现栖息于加拿大不列颠哥伦比亚省小型沿海湖泊的独居泛化型三棘刺鱼种群，其形态可塑性程度高于同域分布的特化浮游型与底栖型刺鱼种群。祖先海洋刺鱼的表型可塑性水平较低，与同域刺鱼种群相近，这表明泛化种群的高可塑性是近期演化而来的。对野生种群的检测结果显示，平均性状值介于底栖型与浮游型之间的种群，其形态变异程度确实更高。本研究数据表明，在开拓新环境后，种群可针对生态位利用方式的改变快速演化出表型可塑性。